package com.gowants.pems.util;

public class VerifyIdCard {
	
	 // wi =2(n-1)(mod 11);加权因子  
    final int[] wi = { 7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2, 1 };  
    // 校验码  
    final int[] vi = { 1, 0, 'X', 9, 8, 7, 6, 5, 4, 3, 2 };  
    private int[] ai = new int[18];  
  
    public VerifyIdCard() {  
    }  
  
    // 校验身份证的校验码  
    public boolean verify(String idcard) {  
        if (idcard.length() == 15) {  
            idcard = uptoeighteen(idcard);  
        }  
        if (idcard.length() != 18) {  
            return false;  
        }  
        String verify = idcard.substring(17, 18);  
        if (verify.equals(getVerify(idcard))) {  
            return true;  
        }  
        return false;  
    }  
  
    // 15位转18位  
    public String uptoeighteen(String fifteen) {  
        StringBuffer eighteen = new StringBuffer(fifteen);  
        eighteen = eighteen.insert(6, "19");  
        return eighteen.toString();  
    }  
  
    // 计算最后一位校验值  
    public String getVerify(String eighteen) {  
        int remain = 0;  
        if (eighteen.length() == 18) {  
            eighteen = eighteen.substring(0, 17);  
        }  
        if (eighteen.length() == 17) {  
            int sum = 0;  
            for (int i = 0; i < 17; i++) {  
                String k = eighteen.substring(i, i + 1);  
                ai[i] = Integer.valueOf(k);  
            }  
            for (int i = 0; i < 17; i++) {  
                sum += wi[i] * ai[i];  
            }  
            remain = sum % 11;  
        }  
        return remain == 2 ? "X" : String.valueOf(vi[remain]);  
  
    }  

}
